This is from my Lo-tech card with SN76489 chip: https://youtu.be/WD8snfTl8iISadly the recording is very soft, but you can hear that the noise channel sounds pretty much 'correct', and different from yours.I used the MODIAC.EXE patched version found on oldskool.org (so Maniac Mansion v1).

I assume everyone is using TI marked chips in their cards, but different chips appear to exhibit different behavior. As I indicated in that article, early Tandys can have the TI chips, but the majority of Tandy 1000s have chips with the NCR behavior. Whether you will get chips with the NCR behavior appears to be a roll of the dice.

i spend half the day rewiring my prototyp card and trying different approaches to make it less noisy.it seems i had some success and full reroute is in progress,also optimizing the card for "building kits" is in progress,Placing all capacitors in same direction and ic's..

I am very much looking forward to buying one of these boards from you when they are finished!It would be great if I could also buy one of those lotech isa compactflash pcbs from you together with the other board, if that is possible!